Compressor



United States Patent [56] References Cited UNITED STATES PATENTS 134,626 H1873 Barden 103/175 349,342 9/1886 Eibler..... 230/188 545,399 8/1895 Wilson 103/175 655,120 7/1900 Renno 230/188X 1,621,913 3/1927 Longacre 230/21 Primary Examiner-Robert M. Walker AltomeysCarl R. Horten, David W. Tibbott and Bernard J.

Murphy ABSTRACT: A piston-type compressor having spaced apart coaxial cylinders spacially enclosed in a housing, with the one space providing an intake passage and the other space providing a pulsation bottle or plenum chamber and discharge passage.

Patenfed Nov. 24, 1970 Sheet R 5 m@ MM A .l M m L m Patented Nov. 24, 1970 3,542,493

Sheet 2 012 WILL/AM 7. ALDERSO/V COMPRESSOR castings, are so configured and arranged that the castings are basically in tension; Accordingly, their castings are of necessity tbick-walledand heavy.

Additionally, known piston-type gas compressors require separate pulsation bottlesor tanks into which the intake gas or the subsequently compressed gas is directed to overcome or damp the pulsed output.

It is an object ofthe present invention, then, to provide a piston-type gas compressor built up from simply formed and coaxially disposed members.

lt is another object of the present invention to provide a piston-type gas compressor formed of castings which. due to the novel compressor arrangement. are basically in compression.

Another object of this invention is to provide a gas compressor of the piston-type requiring no bottles or receiver tanks.

A feature of this invention comprises the use of coaxial, cylindrical castings enclosed in a surrounding steel housing.

Another feature of this invention is the disposition ofan annular intake chamber about the piston-cylinder.

Another feature of this invention is the provision of an encompassing plenum chamber or housing to damp pressure pulsations in the discharge ofthe compressor. I

A number of marked advantages are realized by my novel compressor, and some of these noted below,

1. Safety. Known gas compressors, when subject to excessive pressure, are liable to explode. As the cylinders thereof are customarily of cast metal, the cylinders manifest a frangible disintegration. Accordingly, as a severe hazard to workers, the failing compressor cylinders impel fragments of cast metal about the installation area. The compressor of the instant disclosure is encased in a steel shell which is not frangible; at the worst, on failure, the shell only ruptures.

2, Flow. The valving of my compressor is dispersed radially and axially about and along the structure. lnlet and outlet valves need not be disposed in apposition relative given inlet and outlet ports. My compressor structure communicatesconfined ports with wide voluminous, and annular inlet and outlet plenums. Accordingly, a more efficient flow, for being a less constricted flow, ofgas is accommodated.

3. Volume. The inlet and outlet plenums" priorly noted are generously commodious, thus, they effectively damp inlet and receiver pulsations and eliminate the need for pulsation bottles. I

4. Assembly. My compressor structure is formed, principally, of three coaxial cylinders having O-ring seals and simple and limited bolting, accordingly, the overall unit is easily joined and easily disassembled for maintenance.

5. Light weight. The structure taught herein employs the receiver pressure in the encompassing plenum to maintain the inner cast cylinders substantially in compression. Thus, the cast cylinders are thin-walled and lighter.

6. Limited machining. The three cylinders are simply configured elements,joined by O-rings and simple bolting, which confine the valving therein partially by the receiver" pressure held within the outer steel shell. Thus, a multitude of studs need not be arranged about each valve to insure its re tention in the structure. Only limited machining of ancillary components, and tapping of a small number of bolt holes needs to be undertaken to fabricate my compressor.

Further objects, features, and advantages of this invention will-become more apparent by reference to the following description taken in conjunction with the accompanying drawings, in which: g

FlG..l is a cross-sectional view of one embodiment of the compressor according to the invention;

FIG, 2 is a perspective side view of another embodiment of the compressor with the housing partially cutaway to show the inner construction;

FIG. 3 is a cross-sectional view of an alternate embodiment of a safety type access hole cover usable in the compressors of FIGS. l and 2; and

HQ. 4 is a cross-sectional view of an alternate embodiment of the novel compressor with both inlet and outlet ports disposed on the same side.

As shown in FIG. l. the compressor. indicated generally at 1, has a piston 2 and rod 3 disposed uirhm an inner or first cylinder 4 of cast iron. This tirst cylinder 4 is designed to withstand. in tension, the fluctuating differential pressure between the inlet and the discharge o fthe compressor.

A cast iron second cylinder 5 is eoaxially disposed about first cylinder 4', with first cylinder 4, it forms an inlet passage 6 completely around the first cylinder 4. f A steel housing 7 which surrounds the first and second cylinders 4 and 5 is subjected to, and designed to withstand, the pressure differential between atmospheric and discharge pressures. It will be noted that this pressure differential is relatively constant since the space between cylinder 5 and housing 7 forms, a pulsation chamber and discharge passage 8. Chamber and passage 8 has asufl'i'cient volumeto markedly reduce or eliminate the pulsations. Accordingly, cylinder 5 is exposed to a relatively constant compressive force.

The foregoing, then, are the basic: parts, each of which can be manufactured separately and assembled with the additional, ancillary components to form the complete compressor. Specifically, the FIG. 1 embodiment of my novel eom pressor has an overall'outside diameter of 37 inches. The steel housing 7 is We inch thick. First cylinder 4 is a 1 /2 inch casting which defines a 12 inch bore and accommodates a 15 inch piston stroke. Second cylinder 5 is also a casting l /e inch thick. It has an inside diameter of 23 inches and forms the inlet passage 6 as an annular space 4 inches in width and 2 feet in length. I

Assuming an inlet pressure of 500 p.s.i., andan outlet pressure of i000 p.s.i.,the walls of my compressor need only be sufficient in strength to withstand the following stresses:

first cylinder 42,000 p.s.i. in tension;

secondcylinder 53,500 p.s.i. in compression; and

the steel housing 7--12,000 p.s.i. in tension.

The relative volumes of the inlet and discharge passages 6 and 8, given as ratios to the displacement volume of one end of first cylinder 4. are approximately 5 to l and 12.4 to 1.

respectively, And with this, the total weight of the cast iron components is computed to be but 4,000 pounds.

Simple access covers 9 are provided for getting at inlet or discharge valves l0.and 11 disposed between the first and second cylinders 4 and 5. The covers 9 are sealed by O-rings l2, and held in place by retainers ll3, retaining rings 14, and bolts 15. I The housing 7 has a plurality of short, cylindrical annuluses 16, integral therewith, disposed axially therealong and radially thereabout. The annuluses to penetrate the housing 7 and provide bores 17 through which the aforementioned access is provided, and in which the covers 9 are sealed. Each annulus 16 has a circumferential groove 18 formed therein which cor responds with a circumferential shoulder 19 formed in each cover 9. The rings 14 being ofthe expansion type, seat in the grooves 18 and shoulders 19 to restrain the covers against outward movement, i.e., radial movement away from cylinder 5. Retainers 13 are disposed across the annuluses l6 and mount the bolts l5 which are threaded into the covers 9. Thus, the bolts 15 and retainers l3 restrain the covers 9 against inward movement.

" mit thcpassag'e of the and a piurality of radially disposed inlet aperby, and within,

nular groove 41 thereof to receive a retaining ring 42.'A

The inlet valves disposed on one side-ofthe compressor, I

are of conventional desig'm'andhave side-openings 20 to pe'rgas therethrougli from the inlet opening 21, inlet pipe 22 tures23 formed in an axial'end of first cylinder 4 and juxtapositionally formed in'an' end cap 24. inlet pipe 22 seals the pulsation chamber and dischargepassage 8 from the inlet passage 6. It is end cap 24 which receives the inlet pipe 22. The gas passes through inlet pipe 22, through apertures 23, into the inlet passage first cylinder 4, as indicatedby the full-lined arrows in FIG. 1.

I disposed on the side of the corn The discharge valves 11, V I pressor opposite the inlet valves 10, are of cylindrical form,

and seal the inlet passage 6 fr'om the discharge gas by means of the valve walls 25. Theyprovide a unidirectional flow of pressurized gas from first cylin der 4- into the pulsationchamber and discharge passage 8, as indicated by the dashed-lined arrows.

.luxtapositioned apertures 26 and 27', formed in cylinders and 4, respectively, receive the valves and 11. Apertures26 have. a sin gle, given diameter whichcorresponds to the outside diameter of the valves. Apertures 27 have a first, given dia'rrie: ter of the same dimension as that of apertures 26; also, they have a second diameter, smaller'than the first, which defines,

thercbetween, an annular shoulder-where said first and second diameters interface. That end of each-valve which is more proximate to piston2 is 'disposed'within aperture 27-,and abuts the annular shoulder. The otherendof each valve is confined its respective aperture 26. O-ri ngs. 28' are disposed about either ends of the'valves 10 and; set in an- 6, through the valves 10 and then to the and 4 6 in theouter' surface thereof, Groove .45 is provided to receive an"Q- ri'ng -fj4,7 tol'seal between the mating surfaces of nular grooves 29 formed in the outer valve surfaces, they seal 4 the valves in the apertures 26 and 27. The abutting of the valve ends against theannular shoulders ofapertu'res 27 prohibits the inward m o vement,.i.e., toward piston 2, of the valves. A retainer bar 30, having a length-considerably greater;

than the diameter-of the valves, is disposed across that end of each valve which is set. in aperture 26. Each bar 30 extends across a valve and-is drilled through at theends thereof, to receive a pair of machine screws 31. The .screws 31 are threadedly secured in tapped holes in cylinder 5. Screws 31 and bars 30, then, prohibit the outward movement of the valves. g

it is to be noted that it is not bars 30 alone which prohibit outward movement of the valves. .Pulsation chamber and discharge passage 8' defines a plenum, a "receiver", for the compressed gas product. Accordingly, the storedpressurized product bears against the surfaces of valves 10 and 11 which are exposed to chamber and-passage 8, and urges the valves against the annular shoulders ofapertures 27.

formed in that end of first cylinder 4 which is adjacent the band 44 and rim 40.=Groove 46 is formed therein to interface with groove 41, the two grooves being joined to receive retainv i'ng ring 42*therebetween'. With the positioning of cover 43 within rim 40, and with the interface of grooves 46 and 41, there is formed a terminal step 48 at the juncture of band 44 and rim '40. Step 48 is so disposed to receive an L-shaped retainer ring 49. Ring 49 nests in step 48, andthe inner radial surface thereof receives bolts 50 for fastening thereof to band 44 and against rim 40. Accordingly, cover 43 is constrained against axial movement relative the housing 7.

End block 37, in that it s integral with first cylinder 4, provides a rigid support for the compressor. lt-receives studs 51 which,. with nuts -52 secured thereto. against a mounting member 53, hold the first and second cylinders 4 and 5 in place. End block 37 is nested in an annular cup 54 formed in the rod'end of-the steel shell7.

It is to be noted that the design of my novel compressor incorporates the 'wide use of O-rings as sealing elements betw'e'en mating components. O-rings 28 seal the valves 10 and 11; they insure against the leakage of inlet gas past inlet valves 10 into pulsation chamber 8 and against leakage of pressure pressurized gas past outlet valves 11 into inlet passage 6. A pair of Qi-rings 55, and an O-ring 56, seal against gas leakage between the mating surfaces of the first and second cylinders 4, 5, and the mating surfaces of end block 37 and the annular cup 54. Finally, O-rings 57,58 and 59, and earlier noted O-ring 47, satisfy similar sealing functions with respect to inlet pipe 22 end cap 24, andcover 43.

nular gaskets can be disposed between the shouldered recesses-in cylinder 4 (in which valves 10 and 11 seat), and the ring '49 and the rim 40, and beneath retainer ring 33. Also, a

endof the valvesGasketing can bedisposed between retainer gasket can be' positioned between end block 36 and its mounting surface in shell 7, and between the shouldered recess in end block 33 (in which cylinder 5 seats), and the end of cylinder 5.

Steel housing 7 is shown as formed of three sections, a cylindrical section 60,a rod-end cap section 61, and a rod-end platesection 62, the three beingwelded together at areas 63.

I A flanged outlet pipe 64 is welded in place in the side of the End cap (or cylinder head 24) isiset in'an annular recess 32 inlet opening 21. The'end cap 24' is held in place by a retainer ring 33 studs 34, and nuts 35,- and seals the end of first cylinder 4. It also cooperates with retainer ring 33to hold the second cylinder 5 .in place. Studs 34, passing through the ring 33 are secured in the end of the first cylinder 4. First cylirtder'4 has an end block 36 integral therewith, at the end'of the cylinder which is opposite'the inlet opening ZL'The end block 36 has a first given diameter 37 and a smaller diameter 38 immediately adjacent thereto. The interface of diameters 37 and 38 forms a recessed shoulder 39 which receives the corresponding end of second cylinder 5 thereon. Retainer ring 33 overlies that end of second cylinder 5'which' is adjacent the inlet opening 21. Accordingly, the fastening of ring 33 to first'cylinder '4 applies axial force on second'cylinder 5, and causes the latter to be constrained against the shoulder 39.The inlet end of housing 7 terminates in an exposed annular rim 40'. Rim 40 has an ana housing.

A unitized, i.e., one-piece, cap-plate section, corresponding to separate sections 61 and 62, can beprovisioned-in lieu of sections 61 and 62-1-'as a standard dished component.

in the HQ. 2 embodiment of the invention there is illustrated a compressor no more complex of'structure, but valves 19 ah'dllare arranged axially and radiallytherein. The'hcus-' ing "7; and cylinders 4- and S are modifications of housing 7 andcylinders 4 and 5-modified to accommodate mounting of four additional valves. ln this embodiment four inlet valves 10"and four outlet valves are disposed on opposite sides of the compressor, and pairs of outlet valves 11 are disposed therebetween. Accordingly, ad-

ditionalaccess covers 9 are provided in the steel housing 7 As will be evident to those skilled in the art, further embodiments of my inventive compressor can employ more or less valving in alternative dispositions andalinement. For example, an inlet valve and an outlet valve can be paired, in axial alinement, and such pair's disposed radially about the compressor. One of the teachings of my invention is the provision of a generous inlet passage 6 completely surrounding the first cylinder 4 or 4 to insure a steady flow of gas into the first cylinder. Accordingly, it remains only to provide sufficient m s 'a the gas volume into and out of the ir Cylinder.

, The structure of my compressor is very easily formed of 1 three-simple cylinders 4 or 4' 5 or 5 and 60, and mating rings,

plates, and caps or blocks.

leak after an extended useof the compressor. An-

11 are used. Pairs of inlet valves 10 My compressor, in having a commodious inlet passage 6 and an all-encompassing plenum chamber, the latter being pulsation chamber and discharge passage 8, requires no pulsation bottle.

Further, in that housing 7 or 7 receives the pressurized gas, the first and second cylinders coaxially disposed within are basically in compression. Therefore, the castings of these cylinders are thin'walled, yielding in a lighter weight and more economically produced compressor.

ln FIG. 3 is shown a safety-type, inside-out" access cover usable, in lieu of covers .9 shown in FIGS. 1 and 2, in compressors employed in the production of very high output pressures. The safety cover 65 has a firstdiameter 66 which corresponds to the internal diameter of the annulus 16', and a second larger diameter cap 66a for abutting the inner rim of annulus 16'. Cover 65 receives bolt for a secure fastening thereof against the rim, and carries an O-ring 12 for sealing with the wall of annulus 16'. Retainer 67 mounts the bolt 15 and provides a footing on annulus 16' toward which to draw cover 65 tight.

The inside-out cover is so called because that which appears to be the external cap 66a is internally disposed. It is this arrangement which insures against the, blowing of the cover 65 from out of the housing'7.

Cover 65 is mounted in housing 7 by passing the same between housing 7 and second cylinder- 5 after having removed cover, 43.

Clearly, other embodiments of my invention can be configured, without departing from the spirit of my invention. For

example, in FIG. 4 there is shown an embodiment in which the inlet pipe 22 and inlet apertures 23 are dispensed with and cover 43' and end cap'24 (corresponding to cover 43 and cap 24) are formed whole. An inlet pipe 68 is fixed about an inlet opening 69 formed adjacent the mounting end of the now modified shell 7'. lnlet apertures 23', there being a plurality thereof, are formed in and about the axial, mounting end of the second cylinder 70 for communicating pipe 68 with chamber 6.

In this embodiment, shell 7' has an inwardly extending en annulus 73 for receiving second cylinder 70 there within. About and adjacent the furthermost rod-end termination of cylinder 70 is disposedan O-ring 74; ring 74 mostly sets in a recess provided therefor in the cylinder termination, and engages the inwardly facing rim of annulus 73. This sealing engagement closes off chamber 8 from the atmosphere, and insures that the inlet opening 69 will communicate only with chamber 6.

Again, of course, when and as warranted, a gasket can be positioned between the rim of annulus73 and cylinder 70.

In lieu of the bars 30 and screws 31, shown in the embodiments of FIGS. 1 and 2, I teach the use of a single retaining clamp 75 and one machine'bolt 76 to retain two valves 10 or II) in place. By this innovation I teach the economy of one bolt, in place of four, one tapping, in place of four and one retainer, in place of two. To accommodate the one bolt 76, cylinder 70 has a metal buildup 77 equidistant between the respective valves.

This embodiment of FIG. 4 teaches the arrangement of both inlet and outlet pipes 68, 64, on one side of the compressor. Where the user's requirements so warrant, these pipes can be arranged at any angle up to l80 apart. Shell 7' would simply have its inlet opening 69 formed in the other side thereof, with pipe 68-and the related structures-configured to accommodate the alternate opening.

Further, as a matter of choice, an inlet pipe can be placed in penetration of shell 7' (or 7) and cylinder 70 (or 5) between the ends thereof, say midway, about in line with pipe 64 and 180 therefrom. Such an inlet pipe will seal between the atmosphere and chamber 8, while communicating with chamber 6. i Thus, while I have described my invention in connection with specific embodiments thereof, it is to be clearly understood that this is done only by way of example and not as a limitation to the scope of my invention as set forth in the objects thereof and in the accompanying claims.

- lclaim:

I. A gas compressor, comprising:

afirstcylinder:

a' second cylinder coaxially disposed relative said first cylinder;

piston means disposed in one of said cylinders;

a housing enveloping said first and second cylinders; and

said housing and said cylinders having means communicating'therewith for the inlet of gas thereto, and means communicating therewith for the discharge of gas therefrom;

wherein:

said first and second cylinders have mating surfaces at corresponding axial ends thereof which are joined together; and

said first cylinder and said housing having mating surfaces at corresponding axial ends thereof which are joined together.

2. A gas compressor, according to claim I, wherein said inlet'and discharge means include means disposed between said first and second cylinders for valving the inlet and discharge. of gas, and intake means and exhaust means disposed in said housing.

' 3. A gas compressor, according to claim 2, wherein said first and second cylinders form therebetween a first chamber, and

said first chamber communicates said intake means with said inlet valve means.

4. A gas compressor, according to claim 3, wherein said first chamber'comprisesa pulsation chamber.

5. A gas compressor, according to claim 2, wherein said second cylinder and said housing form th erebetween a second chamber, and said second chamber communicates said outlet valve means with said exhaust means. I v

6. A gas compressor, according to claim 5, whereinsaid second chamber comprises a pulsation chamber.

7. A gas compressor, according to claim 2, wherein said inlet means further include means through connecting said intake means with said first chamber.

8; A gas compressor, according to claim 7, wherein:

said first and second cylinders each have apertures formed therein, at corresponding axial ends thereof, said apertures being juxtaposed;

said housing has a port formed therein; and

said throughconnecting means comprises a conduit communicating said coaxial apertures with said port.

9. A gas compressor, according to claim 8, further including a cover disposed across an axial end of said first cylinder, to seal said axial end thereat; said conduit being in penetration of said cover.

10. A gas compressor, according to claim 2, wherein said inlet and outlet valve means comprises a plurality of inlet and outlet valves disposed axially of said first and second cylinders.

11. A gas compressor, according to claim 10, further includ- 9 ing O-ring seals disposed between said valves and said first-and second cylinders to gas-seal therebetween.

12. A gas compressonaccording to claim I, further including O-ring seals disposed between'said first and second cylinders to seal between said mating surfaces thereof.

13. A gas compressor, according to claim 1, further including an O-ring seal disposed between said first cylinder and said housing to seal between said mating surfaces thereof.

14. A gas compressor, according to claim 1, wherein said housing has access portsformed therein and further includes access covers replaceably secured in said access ports, said ports being adjacent, and providing access, to said valves.

15. A gas compressor, according to claim I, wherein said housing is steel.

16. A gas compressor, according to claim 1, wherein said cylinders are cast iron.

17. A gas compresson'according to claim I, wherein said cylinders define a plurality of surfaces exposed to dynamic gas and said cylinders having means communicating therewith for the inlet of gas thereto. and means communicating therewith for the discharge of gas therefrom;

wherein said inlet and discharge means comprise inlet and discharge valves mounted between said first and second cylinders; and

said housing comprises a plenum chamber for receiving pressurized gas, said pressurized gas being effective to cooperate in retaining said valves in their mounting. 

